There’s an interview with Phil Tippett where he said that the animators would turn in the motion data and the computer technicians would think there was something wrong with it, but when they rendered a rough pass out it looked perfect.
I think one of the main reasons the CGI looks so good nowadays is that they had some of the best stop motion animators in the world animating a tiny armature that would translate the position of the real world model into the computer. So they knew all the tricks of how to get models to animate believably, and technicians were able to bring that forward rather than starting from scratch.
In my experience, animating is more about the final product tricking our brains, rather than realism or precision.
Of course there’s tricks they used like keeping the lighting simple, having on set references for the lighting and colors, and spending months on literally seconds of one CGI character, but yeah, if you look at the computers they were using, it’s absolutely insane what they pulled off.
Oh yeah and the jeep is also CGI when the T-Rex is tearing it up